Science and the Mediterranean diet

Over the past thirty-five years, the main focus of North American dietary recommendations have been to reduce our intake of fat. Not surprisingly, the public has come to associate dietary fat with obesity, cardiovascular disease and cancer, while low-fat or fat-free eating is synonymous with heart health, a trim physique and overall well-being.  


Although nutrition researchers, policy makers and educators have cautioned consumers about the cardiovascular implications of consuming too much animal-derived saturated fat and any amount of trans fats (found in many margarines, fast-foods and commercially baked goods), nutritional guidance that promotes the avoidance of other types of fats has done us a disservice. 


According to Dr. Emilio Ros, an international researcher and director of the lipid clinic at the Hospital Clínic in Barcelona, Spain, eating less fat means we devour something else.


“If you reduce fat, you tend to increase carbohydrates and it’s been known for some time now that some carbs [particularly those that are highly refined and quickly digested] are bad for our weight, diabetes risk and heart health,” said Ros, who was recently in Vancouver for the 10th Congress of the International Society for the Study of Fatty Acids and Lipids.


Reducing our saturated fat intake by eating more processed carbs adversely affects our cardiac health by raising our blood triglyceride levels and lowering the good type of cholesterol, known as high-density lipoproteins (HDLs). 


But replacing saturated fat with unsaturated fats -- namely monounsaturated and polyunsaturated fats, and omega-3 fatty acids found in olive oil, avocado, walnuts, almonds, hazelnuts and fish -- appears to improve our cholesterol levels and prevent heart disease. 


Much of what nutrition scientists know about the health benefits inherit in a high unsaturated fat intake comes from studying the Mediterranean diet, an eating pattern that’s primarily centered around nutrient-rich vegetables, fruits, legumes and whole grains. Small portions of fish, seafood and poultry often replace red meat, which is used as a condiment or reserved for special occasions. Dairy products are consumed in moderate quantities.


Leisurely, home-cooked meals in the midst of physically active days, are an integral part of the Mediterranean lifestyle. On an almost daily basis, modest amounts of wine is imbibed with food; sugary carbonated drinks are rarely consumed. And homemade sweets are considered a treat.


Ros emphasizes that the Mediterranean diet is based on a traditional eating pattern of the 1950s and early 1960s found in natives of Crete, Greece, Italy and Spain. 


“[Today] few people in Mediterranean countries follow the traditional diet and activity level of their ancestors; there’s been a progressive westernization of dietary habits with an increasing consumption of meat, dairy products, industrially-prepared foods, and sweets,” said the nutrition researcher. “Refined sugars and fats in low-cost foods together with increasing sedentariness underlie the epidemic of obesity in the Mediterranean and other areas of the world.”


The scientific basis for the beneficial health effects of the Mediterranean diet isn’t fully understood. We don’t know whether it’s related to the greater ratio of unsaturated to saturated fats, or some other dietary or lifestyle component. Chances are, the benefits are a result of several nutrition and lifestyle variables at play.


At this point, all we can say is that compared to the contemporary Western way of eating, research correlates the Mediterranean diet with increased longevity and lower rates of heart disease, type 2 diabetes and other chronic illnesses.


If North Americans want to reap the potential health perks of this traditional diet, we need to accept that lifestyle and way of eating in its entirety, not simply choose the bits and pieces that appeal to us -- such as drinking wine at meals, dressing our food with olive oil, or munching more nuts.


published in the Vancouver Courier, June 8, 2012